The present invention relates to a signal input system for an electronic equipment such as an automotive navigation system.
As an example of the electronic equipment for selectively processing functions in accordance with an input command through an external input device, an automotive navigation system is provided in a vehicle for selecting a command by operating an operation key and for indicating information such as a route and a direction responsive to the command.
FIG. 9 shows a conventional automotive navigation system. The automotive navigation system comprises a main system 10, a speaker 50, a global positioning system (GPS) antenna 60, a monitor 40 having a display 4, and a remote controller 20 as an input device.
The main system 10 comprises a CPU 11, an input circuit 21, a ROM 13, a SRAM 14, a DRAM 15, a CD-ROM controller 31, an image process circuit 42, a speaker driving circuit 51, and a GPS receiving circuit 61. These elements are connected to the CPU 11 through a bus line 12. The image process circuit 42 is connected to the monitor 40. The speaker driving circuit 51 is connected to the speaker 50. The GPS receiving circuit 61 is connected to the GPS antenna 60. The main system 10 further has a CD-ROM driver 30 connected to the CD-ROM controller 31 and a dual port RAM 41 connected to the image process circuit 42.
The ROM 13 has a plurality of programs such as an input process program 22, a monitor display program 43, a vehicle position detecting program 62, and a calculating program 63.
The remote controller 20 has a plurality of operation keys corresponding to functions of the main system. A desired process is selected by depressing a corresponding key. The remote controller 20 produces a command signal which is transmitted to the input circuit 22 of the main system for selecting a program stored in the ROM 13. The selected program is processed by the CPU 11. Thus, information such as a route guidance is obtained by the monitor 40 indicated on the display 4 thereof.
Operation of the system will be described.
Before starting the vehicle, for example, if the remote controller 20 is operated for selecting a command for reading a map data, a map data 32 is read through the CD-ROM driver 30 and the read data is stored in the DRAM 15. Furthermore, if keys corresponding to commands for setting a goal and a marking are depressed, corners to be tuned WP1 . . . and a destination are set and the set data are stored in the SRAM 14.
During driving the vehicle, if the remote controller 20 is operated to select an operating mode of navigation, a present point of the vehicle detected based on information received from a satellite through the GPS antenna 60 and a turning information at the next corner WP1 are indicated on a map shown on the display 4 of the monitor 40 by markings. Furthermore, if it is determined by calculation that the vehicle approaches the corner, the information is indicated by sound through the speaker 50 such as "Please turn to the right at a next cross.".
On the display 4, it may happen that a picture such as a map is too wide to read a small area or a point to be checked is out of the display. In such cases, the driver may operate the remote controller 20 to expand, contract, or scroll the picture, or perform a search. Furthermore, in order to coincide a heading direction of the vehicle with the route direction on the picture, it is desired to inversely turn the picture. The driver operates the remote controller even if the vehicle is driven.
However, during driving the vehicle, since it is necessary to watch the heading direction and opposed vehicles, it is difficult to operate the remote controller and extremely limited to watch the remote controller.
It is desirable to reduce a burden to the driver for operating the remote controller.